1. Field of the Invention
The present invention relates to a process and computer system for playing an audio compact disk (CD) and, more particularly, to a process and computer system for selectively powering up the system to play an audio compact disk under the condition that the main power for the entire computer system remains turned-off.
2. Description of the Related Art
Generally, a computer which has a compact disk driver (CDD) and a video board for playing motion pictures is known as a multimedia computer. Nowadays, almost all of the computers on the market have the compact disk drive for reading or playing a compact disk-title, an MPEG (Motion Picture Experts Group) video compact disk and an audio compact disk. In the conventional computer system, main power must be supplied to the entire computer system for driving the compact disk drive therein and playing an audio compact disk. Exemplars of typical designs of computer systems and process able to play audio compact disks may be found in such recently issued references as U.S. Pat. No. 5,634,798 to Suh, entitled Compact Disk Player-Incorporated Television Receiver Having A Monitor Power Control Function, U.S. Pat. No. 5,521,854 to Kadowaki et al., entitled Power-Saving Control For A control Unit In A Computer System, U.S. Pat. No. 5,504,908 to Ikeda, entitled Power Saving Control System For Computer System, U.S. Pat. No. 5,617,571 to Tanaka, entitled Method For Controlling Power To Individual Audio-Video Units Making Up An Audio-Video System, U.S. Pat. No. 4,747,041 to Engel et al., entitled Automatic Power Control System Which Automatically Activates And Deactivates Power To Selected Peripheral Devices Based Upon System Requirement, and U.S. Pat. No. 5,511,203 to Wisor et al., entitled Power Management System Distinguishing Between Primary And Secondary System Activity.
Earlier computer systems for playing audio compact disks typically used a system bus, a central processing unit, a random access memory, a read only memory, a video controller, an input/output controller, an IDE controller, an hard disk drive, a compact disk drive, an audio card, speakers, a microcontroller and a switching mode power supply. The system bus interfaces data, commands and interrupt signals among the various devices of the computer system. The I/O controller is connected to the system bus and controls signal input/output operations of the variable peripheral devices such as floppy disk drives, serial ports, parallel ports, and infrared ports. The IDE controller is connected to the system bus controls signal input/output of the hard disk drive and compact disk drive. The hard disk drive and compact disk drive are controlled to read or write data thereon by the IDE controller. Conventionally, the IDE controller is a device for interfacing disk drivers with a computer. In a computer system using the IDE controller, additional boards for interfacing the drivers and the computer are not required since the disk drivers contain disk driver control circuits therein. The audio card receives and manipulates the audio signal from the compact disk drive. The speaker outputs voice signals upon receiving the audio signals. The microcontroller outputs PMS control signals for controlling the power supply according to the control signals generated from the keyboard and the mouse or according to software stored therein. The power supply receives AC power and supplies main power to the entire computer system according to the PMS control signals.
The compact disk drive related parts of the earlier computer system for playing an audio compact disk comprises the power supply for supplying main power to the entire computer system. The power supply is turned on by the operation of a switch. The computer system further includes the compact disk drive. The audio card receives and manipulates the audio signals from the compact disk drive and speakers output voice signals upon receiving the audio signals from the audio card. In operation, a user turns on the power supply by pressing the switch to play an audio compact disk. Then, the main power is supplied to the entire computer system. After supplying the main power, a software for playing an audio compact disk is operated by the user and the compact disk drive outputs the audio signals according to the control signals of the IDE controller. Then, the audio card receives and manipulates the audio signals and the speakers output voice signals upon receiving the audio signals.
I have noticed that in the designs for these earlier systems, the compact disk drive can be operated after supplying the main power to the entire computer system and after executing an operating system for the computer and a software program for playing the audio compact disk. In addition, the microcontroller can not control the switching mode power supply in such a manner that only the compact disk drive can be operated. Therefore, even when the user want to play only the audio compact disk in the computer system, the entire computer system must be turned-on. Thus, approximately 100 Watts of power are needed to play the audio compact disk in the computer system. Namely, many devices which are unnecessary for playing the audio compact disk must be operated. Therefore, if a device of the computer system has malfunctioned, the user can not play the audio compact disk. In addition, it takes a great deal of time to start the compact disk drive since the operating system for the computer must be executed before playing the audio compact disk. Furthermore, the audio quality of the audio compact disk is deteriorated due to the noise generated by the operation of various cooling fans for the CPU and SMPS.